package com.lxl.servlet;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.lxl.config.SystemConfig;
import com.lxl.message.JsonMsgProvider;
import com.lxl.message.MsgStatus;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.log4j.Logger;

public class UploadServlet extends HttpServlet {
    private static Logger logger = Logger.getLogger(UploadServlet.class);

    // 上传配置
    private static final int MEMORY_THRESHOLD   = 1024 * 1024 * 3;  // 3MB
    private static final int MAX_FILE_SIZE      = 1024 * 1024 * 40; // 40MB
    private static final int MAX_REQUEST_SIZE   = 1024 * 1024 * 50; // 50MB

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 检测是否为多媒体上传
        if (!ServletFileUpload.isMultipartContent(request) || request.getParameter("path") == null) {
            // 如果不是则停止
            PrintWriter writer = response.getWriter();
            writer.println(new JsonMsgProvider().provideMessage(MsgStatus.REQUEST_ERROR, "Request Error."));
            writer.flush();
            return;
        }

        // 配置上传参数
        DiskFileItemFactory factory = new DiskFileItemFactory();
        // 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中
        factory.setSizeThreshold(MEMORY_THRESHOLD);
        // 设置临时存储目录
        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
        ServletFileUpload upload = new ServletFileUpload(factory);
        // 设置最大文件上传值
        upload.setFileSizeMax(MAX_FILE_SIZE);
        // 设置最大请求值 (包含文件和表单数据)
        upload.setSizeMax(MAX_REQUEST_SIZE);
        // 中文处理
        upload.setHeaderEncoding("UTF-8");

        String reqParamPath = request.getParameter("path");
        // 构造存储路径
        String uploadPath = SystemConfig.SERVER_ROOT_PATH + File.separator + reqParamPath.replace('_',File.separatorChar) + File.separator;
        // 如果目录不存在则创建
        File uploadDir = new File(uploadPath);
        if (!uploadDir.exists()) {
            uploadDir.mkdir();
        }

        try {
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(request);

            if (formItems != null && formItems.size() > 0) {
                // 迭代表单数据
                for (FileItem item : formItems) {
                    // 处理不在表单中的字段
                    if (!item.isFormField()) {
                        String fileName = new File(item.getName()).getName();
                        String filePath = uploadPath + File.separator + fileName;

                        File storeFile = new File(filePath);
                        if (storeFile.exists() && storeFile.isFile()){
                            logger.info("Exist and delete file: " + filePath);
                            storeFile.delete();
                        }
                        logger.info("Save file: " + filePath);
                        item.write(storeFile);
                    }
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
            logger.error(ex.getMessage());
        }
        response.getWriter().write(new JsonMsgProvider().provideMessage(MsgStatus.SUCCESS, null));
    }
}
